CakePHP ships with a default controller PagesController.php. This is a simple and optional controller for serving up static content. The home page you see after installation is generated using this controller. If you make the view file app/View/Pages/about_us.ctp you can access it using the url http://example.com/pages/about_us. You are free to modify the Pages Controller to meet your needs.
When you “bake” an app using CakePHP’s console utility the Pages Controller is created in your app/Controller/ folder. You can also copy the file from lib/Cake/Console/Templates/skel/Controller/PagesController.php.
Changed in version 2.1: With CakePHP 2.0 the Pages Controller was part of lib/Cake. Since 2.1 the Pages Controller is no longer part of the core but ships in the app folder.
Do not directly modify ANY file under the lib/Cake folder to avoid issues when updating the core in future.